From: Benjamin Coddington <ben.coddington@hammerspace.com>
To: Trond Myklebust <trondmy@kernel.org>, Anna Schumaker <anna@kernel.org>
Cc: linux-nfs@vger.kernel.org,
Jonathan Curley <jcurley@purestorage.com>,
Mike Snitzer <snitzer@kernel.org>,
Jeff Layton <jlayton@kernel.org>,
Junrui Luo <moonafterrain@outlook.com>
Subject: [PATCH v3 21/24] NFSv4/pnfs: Grow the deviceid cache hash table
Date: Fri, 4 Sep 2026 12:53:20 -0400 [thread overview]
Message-ID: <b57232b3d0b4b528f8a3433a6d59badb47c37944.1788530385.git.bcodding@hammerspace.com> (raw)
In-Reply-To: <cover.1788530385.git.bcodding@hammerspace.com>
The global deviceid cache has 32 buckets shared by every server and
layout type. Striping deployments initially anticipate device counts
scaling to 1024 or more devices, which leaves those chains 32 entries
deep for every resolution to walk.
Grow to 256 buckets, four deep at that scale, for 2KB of BSS on
64-bit.
Assisted-by: Claude:claude-fable-5
Signed-off-by: Benjamin Coddington <bcodding@hammerspace.com>
---
fs/nfs/pnfs_dev.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/fs/nfs/pnfs_dev.c b/fs/nfs/pnfs_dev.c
index a3b28409539a..e8143977965c 100644
--- a/fs/nfs/pnfs_dev.c
+++ b/fs/nfs/pnfs_dev.c
@@ -40,8 +40,11 @@
/*
* Device ID RCU cache. A device ID is unique per server and layout type.
+ *
+ * 256 buckets keeps the chains short at the 1024-or-more devices a
+ * striping deployment expects, for 2KB of BSS on 64-bit.
*/
-#define NFS4_DEVICE_ID_HASH_BITS 5
+#define NFS4_DEVICE_ID_HASH_BITS 8
#define NFS4_DEVICE_ID_HASH_SIZE (1 << NFS4_DEVICE_ID_HASH_BITS)
#define NFS4_DEVICE_ID_HASH_MASK (NFS4_DEVICE_ID_HASH_SIZE - 1)
--
2.53.0
next prev parent reply other threads:[~2026-09-04 16:53 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-04 16:52 [PATCH v3 00/24] NFS: flexfiles device notifications and caching for wide striped layouts Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 01/24] NFSv4/pnfs: Free the netid when draining a data-server address list Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 02/24] NFSv4/flexfiles: Use the full 64-bit stripe_unit Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 03/24] NFSv4/pnfs: bound the CB_NOTIFY_DEVICEID array count before allocating Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 04/24] pNFS: Fix CB_NOTIFY_DEVICEID CHANGE to consume ndc_immediate Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 05/24] NFSv4/flexfiles: Use the full 64-bit offset for read DS selection Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 06/24] NFSv4/flexfiles: Bound page coalescing on the absolute stripe offset Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 07/24] NFSv4/filelayout: Anchor page coalescing on pattern_offset Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 08/24] NFSv4/flexfiles: Reference the device node across DS setup Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 09/24] NFSv4/flexfiles: Carry the device node reference across each I/O Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 10/24] NFSv4/flexfiles: Hold a device node reference for layoutstats encoding Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 11/24] NFSv4/flexfiles: Make the pinned device node pointer RCU-managed Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 12/24] pNFS: Add a reresolve_deviceid layout driver hook Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 13/24] NFSv4/flexfiles: Implement in-place device re-resolve on CHANGE Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 14/24] NFSv4: Dispatch CB_NOTIFY_DEVICEID CHANGE to an in-place refresh Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 15/24] NFSv4/flexfiles: Honor ndc_immediate on CB_NOTIFY_DEVICEID CHANGE Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 16/24] pNFS: Discard a GETDEVICEINFO reply that raced a CHANGE notification Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 17/24] pNFS: Add deviceid reference query and collection walkers Benjamin Coddington
2026-09-10 16:58 ` Anna Schumaker
2026-09-10 17:24 ` Benjamin Coddington
2026-09-10 18:05 ` Anna Schumaker
2026-09-04 16:53 ` [PATCH v3 18/24] NFSv4/pnfs: Recover revoked layouts on a deleted deviceID Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 19/24] NFSv4/pnfs: Confirm a deviceID delete via GETDEVICEINFO Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 20/24] NFSv4/pnfs: Dispatch CB_NOTIFY_DEVICEID DELETE to race recovery Benjamin Coddington
2026-09-04 16:53 ` Benjamin Coddington [this message]
2026-09-04 16:53 ` [PATCH v3 22/24] NFSv4/pnfs: Re-home the data-server cache onto hash buckets Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 23/24] NFSv4/pnfs: Key the data-server cache by its address set and version Benjamin Coddington
2026-09-04 16:53 ` [PATCH v3 24/24] NFSv4/flexfiles: Add a dataserver_nconnect cap Benjamin Coddington
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